Class solo duty quests can easily take care of the "learning" aspect of blue mage. Heck, they could make it so that you start a lvl 50 blu mage quest, learn a bunch of abilities to start, then every 2 levels, learn one ability via solo duty.

Also, this
Quote Originally Posted by Reiryuu View Post
There have been a lot of suggestions for Blue Mage in FFXIV. What it boils down to is this: If the devs want to implement it, they will find a way to do it. That simple.